Citation:
Zheng-guo Cai, Yuushou Nakayama, Takeshi Shiono. SUBSTITUENT EFFECTS OF tert-BUTYL GROUPS ON FLUORENYL LIGAND OF [t-BuNSiMe2Flu] ZrMe2[J]. Chinese Journal of Polymer Science,
2008, 26(5): 575-578.
SUBSTITUENT EFFECTS OF tert-BUTYL GROUPS ON FLUORENYL LIGAND OF [t-BuNSiMe2Flu] ZrMe2
摘要:
[t-BuNSiMe2(2,7-t-Bu2Flu)]ZrMe2 and [t-BuNSiMe2(3,6-t-Bu2Flu)]ZrMe2 were synthesized, and the solid structure of complex [t-BuNSiMe2(2,7-t-Bu2Flu)]ZrMe2 was elucidated by single crystal X-ray analysis. These complexes were applied for propylene polymerization using dried modified methylaluminoxane as a cocatalyst at 0οC and 20οC in toluene. Both systems did not show activity at 0οC, but they conducted the polymerization at 20οC. The introduction of t-butyl substituents to the fluorenyl ligand improved the activity more than six times regardless of the position of the substituents, and both systems gave low molecular weight polypropylenes (PP) with narrow molecular weight distribution. The introduction of t-butyl substituents also improved the syndiospecificity and [t-BuNSiMe2(3,6-t-Bu2Flu)]ZrMe2 gave highly syndiotactic PP with the syndiotactic pentad of 0.91 and the melting point of 145οC.
English
SUBSTITUENT EFFECTS OF tert-BUTYL GROUPS ON FLUORENYL LIGAND OF [t-BuNSiMe2Flu] ZrMe2
Abstract:
[t-BuNSiMe2(2,7-t-Bu2Flu)]ZrMe2 and [t-BuNSiMe2(3,6-t-Bu2Flu)]ZrMe2 were synthesized, and the solid structure of complex [t-BuNSiMe2(2,7-t-Bu2Flu)]ZrMe2 was elucidated by single crystal X-ray analysis. These complexes were applied for propylene polymerization using dried modified methylaluminoxane as a cocatalyst at 0οC and 20οC in toluene. Both systems did not show activity at 0οC, but they conducted the polymerization at 20οC. The introduction of t-butyl substituents to the fluorenyl ligand improved the activity more than six times regardless of the position of the substituents, and both systems gave low molecular weight polypropylenes (PP) with narrow molecular weight distribution. The introduction of t-butyl substituents also improved the syndiospecificity and [t-BuNSiMe2(3,6-t-Bu2Flu)]ZrMe2 gave highly syndiotactic PP with the syndiotactic pentad of 0.91 and the melting point of 145οC.
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